Two conservative Democrats who are up for re-election in 2014 held back from immediately joining the GOP effort to stop the Senate from voting on the gun-control bill.

“This is an issue that we should debate,” said Sen. Mary Landrieu (D., La.). The Louisiana Democrat said she plans to wait until she sees the final language of any bipartisan deal on background checks before deciding whether she will support it.

Sen. Mark Pryor (D., Ark.) told reporters that he wanted to “see how this develops” before deciding whether to join the Republican filibuster. “I know that many senators are working to try to get to some sort of compromise,” he said.